Sexual harassment allegations against Democratic Rep. Ruben Kihuen have raised serious doubts about whether he could win re-election, and questions about who could run in the swing Nevada district if he steps aside.

Kihuen has not yet weighed in on his future, even as top Democratic leaders have called on him to resign following a Buzzfeed report detailing sexual harassment and unwanted advances towards a former campaign staffer.

Kihuen was not present for the first votes on the House floor Monday night, but he appeared to return to the nation's capital to cast another vote shortly before 9 p.m., according to the roll call.

Watch: Ryan — ‘We Will Not Tolerate’ Sexual Harassment in Congress

In D.C., leaders including House Minority Leader Nancy Peolosi and Democratic Congressional Campaign Committee Chairman Ben Ray Lujánhave called on Kihuen to resign. And back in Nevada, some Democrats say Kihuen has no chance of winning re-election if he refuses to step aside.

One Democratic operative told the Las Vegas Review-Journal over the weekend that Kihuen was not resigning. Kihuen’s office did not respond to multiple requests for comment on the report on Monday.

Some Democrats in the state believe running for re-election is not an option for the first-term congressman because he would lack the support and the money necessary to win.

“There’s no way Ruben can win in 2018,” said one Democratic operative. “Just flat out, no way.”

Competitive district

Even before these allegations broke, the race was likely to be competitive and expensive. In 2016, outside groups spent more than $11 million in the race, according to Open Secrets. The DCCC spent more than $3 million in Nevada’s 4th District. The NRCC spent more than $6 million.

In 2018, the district was expected to be expensive once again, with a competitive Senate and governor’s races competing for air time in the Las Vegas media market. The district is also among the slate of GOP targets in a cycle where Republicans are largely on defense.

The DCCC has not explicitly stated it would not support Kihuen should he run for re-election. But some are interpreting Luján’s call for Kihuen’s resignation as a sign the committee would not back him.

Two Democratic operatives described Kihuen’s fundraising as lackluster, and said DCCC support would be key to victory.

Kihuen had $486,000 in the bank as of Sept. 30, according to Federal Election documents. Las Vegas City Councilman Stavros Anthony, considered the top GOP contender, had nearly $122,000 on hand after his first fundraising quarter.

“This is another reason why, if local and national Democrats cut him off, he’s so screwed, because he was so reliant on outside help,” said one Democratic operative.

An open seat?

There are still questions as to what happens next, depending on if Kihuen resigns or decides not to run again.

Should he resign and prompt a special election, that could create some headaches for Democrats since special elections are difficult to predict and could clash with a June primary election.

GOP Gov. Brian Sandoval would have seven days after Kihuen’s seat was vacant to issue a proclamation calling for a special election. The election would have to take place within six months of Sandoval’s proclamation.

Also in special elections, the major parties’ central committees choose their nominees, rather than a traditional primary election.

If Kihuen decides not to run, that could open to door for a number of Democrats to run for the seat, which Inside Elections with Nathan L. Gonzales rates Likely Democratic.

Multiple operatives naming the following Democrats as potential contenders: Former Rep. Steve Horsford, who lost in 2014; State Sen. Yvanna Cancela, who represents Kihuen’s old state Senate seat; Clark County Commissioner Chris Giunchigliani, who some doubted would exit the governor’s race; and former Las Vegas city Councilman Steve Ross.

One operative suggested Horsford could be a likely pick, since he is still well-liked, has experience running for Congress, has a natural fundraising base, and lost in a tough year for Democrats.

But one consultant in the state said Democrats should be wary of repeating past mistakes of picking candidates who cannot hold onto the seat, following Horsford’s loss in 2014 and Kihuen’s downfall this year.

“You can’t make the same mistake three times,” the consultant said. “You just can’t.”

When it comes to Nevada politics and choosing the next Democratic nominee in an open seat, one key player is former Democratic Sen. Harry Reid.

“There’s some consternation about Reid and his backing for Ruben, and what people around Reid knew about this sort of behavior,” said one operative.

Reid so far has been quiet on the allegations. But one Democrat said his word could seal Kihuen’s fate.

“The sense that everybody has is once Reid tells him, ‘You’re done,’ then he’s going to have nowhere to go,” said the Democrat. Get breaking news alerts and more from Roll Call on your iPhone or your Android.